Leachability of metals from discrete particles under centrifugation

The focus of this thesis was to investigate the leaching of calcium, copper and zinc from discrete particles of coal ash under various levels of agitation. The latter was accomplished through centrifugation, and was scaled as an agitation index (AI), expressed as the ratio of centrifugal to gravitational forces on ash particles. Particle surface area and leachant pH, and their effect on the leaching of these metals from both crushed and uncrushed ashes were studied.; Obtained results indicate that at agitation index levels of 0.16, 16.2, and 65 mins, leachate zinc concentrations are 130, 251 and 149 ppm respectively. Also, metal concentrations in coal ash leachate increase with increase in particle surface area. The crushing of bottom ash decreases metal concentrations leached compared to those obtained for uncrushed materials (uncrushed fly ash and uncrushed bottom ash).; The use of low pH leachant enhances metal removal from ash at all AI levels.; Finally, metal concentrations increase with decreasing particle size. (Abstract shortened by UMI.)...